The wide distribution of mobile terminals, such as mobile telephones, for example, demands fast data transmission via wireless interfaces and local wireless data networks. Light-emitting diodes (LEDs) can be used for lighting rooms in buildings. Light-emitting diodes, also referred to as LEDs, feature low energy consumption and long service life. Light-emitting diodes provided for lighting rooms inside buildings are modulated with pulse width modulation to enable the luminance level within a room to be set according to the respective requirements. Pulse width modulation for brightness control is also described by experts as “dimming”.
Methods for simultaneous brightness control and data transmission via a light source are already known. It has already been proposed in a patent application filed at the German Patent and Trademark Office on 28.04.2009, to modify a pulse duty factor of the pulse width modulation in individual pulse-width-modulation cycles so that data to be transmitted is encoded by means of such a cycle-dependent pulse duty factor without the set brightness experiencing a change overall. In this case, in order to maintain the set brightness, the value of an arithmetic mean generated over a large number of cycle-dependent pulse duty factors should essentially correspond to the set pulse duty factor.